Field
The disclosed and claimed concept relates generally to electrical interruption equipment and, more particularly, to a testing apparatus that is usable with a switchgear cabinet.
Related Art
Circuit interruption equipment is well known in the relevant art for use in interrupting the flow of current in a protected portion of an electrical circuit. Numerous types of such circuit interruption devices exist and can include circuit breakers, vacuum interrupters, and numerous other types of devices known for such purposes.
One type of circuit interruption system is a withdrawable circuit interruption system such as is depicted generally in FIGS. 1-7. Such a system employs a switchgear cabinet 6 and a circuit interruption device 10 that is mountable thereon and removable therefrom. The switchgear cabinet 6 has an interior 12 within which the circuit interruption device 10 is receivable through an access port 16 of the switchgear cabinet 6. The switchgear cabinet 6 has a number of electrical conductors 22 within the interior 12 that are covered by a shutter assembly 24 to protect personnel in the vicinity of the switchgear cabinet 6 from contact with the electrical conductors 22 in situations when the circuit interruption device 10 is removed from the interior 12 of the switchgear cabinet 6. As employed herein, the expression “a number of” and variations thereof shall refer broadly to any non-zero quantity, including a quantity of one. As can be seen in FIGS. 1-2 and 4-6, the shutter assembly 24 includes a first plate 28 having a plurality of first holes 30 formed therein, a second plate 34 (FIGS. 2 and 4-5) having a plurality of second holes 36 (FIG. 5) formed therein, a pair of abutments 40A and 40B affixed to the first plate 28, and an engagement apparatus 42 that is connected with the first and second plates 28 and 34. The engagement apparatus 42 is depicted in FIGS. 4-5 as including a push bar 46 and a pair of links 48A and 48B that extend between the push bar 46 and the first and second plates 28 and 34. The first and second plates 28 and 34 are cooperable with channels formed in the walls of the switchgear cabinet 6 to move the shutter assembly 24 between a deployed state, such as is depicted in FIGS. 1-2 and 4, and an undeployed state, such as is depicted in FIGS. 5-6. The shutter assembly 24 is spring biased toward the deployed state in which the first and second holes 30 and 36 are offset from one another such that the first and second plates 28 and 34 together form a shield between the electrical conductors 22 and the interior 12 of the switchgear cabinet 6. When the circuit interruption device 10 is removed from the interior 12, the shutter assembly 24 is therefore in the deployed state and covers the electrical conductors 22.
As is best shown in FIG. 1, the switchgear cabinet 6 has a support 52 that is movably situated within the interior 12 and that is movable between an extended position such as is depicted in FIG. 1 wherein a portion of the support 52 protrudes from the interior 12 into the exterior 8 of the switchgear cabinet 6 and a number of retracted positions 52 wherein the support 52 is situated within the interior 12. The support 52 includes a pair of telescoping rails 56A and 56B, and the circuit interruption device 10 includes a number of lugs 58 formed on an exterior surface of its housing. The lugs 58 are receivable on the rails 56A and 56B, such as when the support 52 is in the extended position shown in FIG. 1, wherein the shutter assembly is in its deployed state. As the rails 56A and 56B are telescoped into the interior 12 with the circuit interruption device 10 situated thereon, the circuit interruption device 10 is advanced farther into and along the interior 12 and begins to approach the shutter assembly 24, as is indicated generally in FIG. 2 wherein the circuit interruption device 10 has not yet made physical contact with the shutter assembly 24.
The circuit interruption device 10 includes a drive system 54 that is depicted generally in FIG. 3 and that includes a pin 60 that is situated on a pivotable crank 62. The pin 60 is receivable in a notch 63 that is formed in a structure 64 of the switchgear cabinet 6 that is disposed within the interior 12 of the switchgear cabinet 6. As the crank 62 is pivoted (in the clockwise direction from the perspective of FIGS. 3 and 7), the pin 60 is received in the notch 63, and the circuit interruption device 10 is advanced farther into the interior 12 to a point where the circuit interruption device 10 physically engages the abutments 40A and 40B and the push bar 46. Further advancement of the circuit interruption device 10 into the interior 12 causes the shutter assembly 24 to be corresponding advanced toward the electrical conductors 22 and to move the shutter assembly 24 from its deployed state to its undeployed state that is depicted generally in FIGS. 5 and 6. In the undeployed state, the first and second holes 30 and 36 are aligned with one another to thereby uncover the electrical conductors 22 and to permit finger clusters or other connection structures on the advancing face of the circuit interruption device 10 to be electrically engaged with the electrical conductors 22. It thus can be understood that by advancing the circuit interruption device 10 into the interior 12 by operating the drive system 54 to engage the pin 60 in the notch 63 and to simultaneously engage the advancing wall of the circuit interruption device 10 with the shutter assembly 24, the bias of the shutter assembly 24 is overcome, and the shutter assembly 24 is translated farther into the interior 12 while moving the shutter assembly 24 from the deployed state to the undeployed state and simultaneously receiving the electrical conductors 22 in the aligned first and second holes 30 and 36. Such a condition is depicted generally in FIG. 6.
While such circuit interruption systems have been generally effective for their intended purposes, they have not been without limitation. For instance, since the shutter assembly 24 is caused by the advancing circuit interruption device 10 to simultaneously move toward the electrical conductors 22 while translating the first and second plates 28 and 34 with respect to one another to move from its deployed state to its undeployed state, the proper operation of the components relies upon the shutter assembly 24 and the electrical conductors 22 being situated in pre-established positions with respect to one another. However, it is understood that potential limitations with the manufacturing process and damage that may be sustained by the switchgear cabinet 6 during transportation to its final location may result in improper positioning of the electrical conductors 22 or the shutter assembly 24 or both. Such misalignment can be a problem because it can inhibit the circuit interruption device 10 from electrically engaging the electrical conductors 22 and because an attempt to receive the circuit interruption device 10 into the interior 12 can cause the shutter assembly 24 to engage the electrical conductors 22 themselves and thereby cause damage. Additionally or alternatively, such misalignment cannot be observed from the exterior 18 of the switchgear cabinet 6 because of the visually obstructive presence of the circuit interruption device 10. As is understood from an arrow 65 that is depicted in FIGS. 2 and 6, the circuit interruption device 10 itself obstructs a view from the exterior 18 of the shutter assembly 24 in its undeployed state. Improvements therefore would be desirable.